Gas-Phase Detection of UTI-Causing Bacteria Using Off-the-Shelf Gas Sensors and Change-Point Detection

The combination of commercial electronic gas sensors and change-point detection (CPD) methodology can detect infection-causing pathogens by monitoring their gas phase emissions (e.g., volatile organic compounds (VOCs) and other species) in cultures. Urinary tract infection (UTI)-related gram-negative and -positive bacteria Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa), Enterococcus faecalis (E. faecalis), and Streptococcus agalactiae (S. agalactiae) were cultured at various concentrations in blood agar plates for up to 24 h. Off-the-shelf electronic gas sensors were placed inside each culture dish to monitor the gas phase emissions of the cultures over time. Offline data analysis using the isolate-detect (ID) CPD methodology identified diagnostic change points for concentrations above the clinical threshold for infection ( $10^{{4}}$ cfu/mL) before 10 h. This result is significantly faster than the current clinical standard for the detection of bacterial infection in agar plates which takes overnight (O/N).